缺少的维护工具 和 MRO 库存控制

ReliabilityConsulting WhitePaper

November2018

TheMissingToolforMaintenanceandMROInventoryControl

ByRustenSmith

TheMissingToolforMaintenanceandMROInventoryControl

November2018

/opcertcon

PAGE

10

TableofContents

TOC\o"1-1"\h\z\u

BOMs–AMaintenance&MROInventorySavingsModel 3

BOMDefinitions 4

IndustryPacesettersHaveBOMGoals 4

IndustryPacesettershaveaBestPracticeBOMStrategy 4

TypicalBestPracticeMROBOMProcesses 5

TypicalBOMStructure 5

TypicalBOMElementDefinitions 6

PotentialMROInventorySavings 6

DistributionofPotentialMROInventorySavings 6

PlantSavingsfromMROBOMs 7

YourTotalPotentialBOMSavings 8

InvestmentcosttogaintheMROBOMportionoftheMROInventorySavings 8

AppendixA 9

BOMs–AMaintenance&MROInventorySavingsModel

Emersonhasperformedhundredsofplantassessmentsinawiderangeofindustries,includingChemicalProcessing,HeavyMetals,Pharmaceuticals,PowerGenerationandawidevarietyofLightManufacturing.Duringthecourseoftheseassessments,EmersoncametotheconclusionthataconsistentlymissingmaintenancebestpracticeistheavailabilityofaccurateBillofMaterialsforplantequipment.OnlyahandfulofplantsvisitedbyEmersonhavecompleteBillofMaterialsavailable,whichincorporatedthemajorityofthesparepartsintheirMROinventory.Notsurprisingly,theseplantsarealsoconsidewredpacesettersintheirrespectiveindustries.

Thefocusofthisreportisonthedifferentiatorsthatseparatethesefewpacesettersfromtheircompetitors.ThefollowingchartdepictstheresultspossiblewhencompleteBOMsareinplace.Thechartisbasedonrealdatafromamid-westernrefinerythatwasundertakingmanycapitalimprovementprojectsduringtheeight-yeartimespanrequiringtheadditionofnumeroussparepartstosupportnewequipment.Thechartshowsthatinspiteofalargeincreaseintheaccumulativevalueofnewspareparts,theoveralleffectonthetotalinventoryvaluewasnegligible.WhileotherpracticessuchasregularevaluationofinventorylevelsusinganEOQandorderpointmodelandthedailypracticeofABCcyclecountingcontributedtothecontrolofthetotalinventory

value,theprimaryreasonfortheresultsdepictedinthechartwerebecauseofaccurateandcompleteBOMs.Thesparepartsforoldequipmentremovedfromservicewereeasilyandsafelydeletedfrominventorybecausetheplantuseofeverystockedsparepartwasknown.

BOMDefinitions

TherearemanydifferentnamestiedtothelistsofpartsthatarecarriedinanMROinventorytoallowthepropermaintenance

ofaplant’sequipment.Toavoidconfusioninourdiscussions,thefollowingdefinitionsareprovidedforclarificationoftheterms

wewilluse:

OEMBOM:Thecompletelistingofallcomponentsusedbytheoriginalequipmentmanufacturertobuildapieceofequipment.

WorkOrderBOM:Thelistingofmaterialsrequiredtoaccomplishtheworkdescribedinthejobplan.

MROBOM:Thelistingofcomponentstheequipmentownerhasdeterminedarenecessarytomaintaintheequipment.

StockedParts:ThecomponentsthatarelistedonaMROBOMandarecarriedininventory.

Non-stockedParts:ThecomponentsthatarelistedonaMROBOMandareorderedonrequestonly.TheMROBOMwillbeourprimarytopicofdiscussion.

IndustryPacesettersHaveBOMGoals

IntheareaofMROBOMs,EmersonresearchhasdeterminedthatthedifferentiatorbetweenpacesettersandtherestofthepackisthatthepacesettershaveclearlydefinedgoalsplantpersonnelinvolvedwithMROBOMsareworkingtowards.Infact,oneinterestingpointisthatcomprehensiveMROBOMstendtoonlyexistinpacesetterplants.Thefollowingarethemostcommonlyoccurringgoalsthepacesettershaveachievedorareworkingtowards:

Allstockedsparepartsanddesirednon-stockedpartsareassignedtoMROBOMsonallapplicableequipment.Newequipmentisaddressedprocedurally.

WhentheinitialMROBOMprojectiscomplete,sparepartsthathavenotbeenlinkedtoequipmentareremovedfromtheMROinventory.

Someformofbestpracticeanalysismethod(s)isusedwhendevelopingMROBOMs.

IndustryPacesettershaveaBestPracticeBOMStrategy

Thefollowingstrategiesdifferentiatepacesetters:

PacesettersuseastandardmethodologytobuildMROBOMs.Thismethodologyisingrainedintheplantcultureandfostersusingconsistentproceduressothattherightpartsarestockedtosupportplantproductionandcostcontrolgoals.Emersonhasfoundthatstandardmethodologiestypicallyincludethefollowingpractices:

Formalanalysisisperformedtoidentifycriticalwearableparts.Thisanalysisisperformedataminimumonallequipmentcategorizedascriticaltotheplant’soperations.TheresultsfromthisanalysisbecomethemaindriverforMROBOMdevelopmentforcriticalequipment.Equipmentdeemedlessimportanttotheplants’operationswillhavewearablepartsidentifiedbyusinglessintensiveanalysis.

PriortobuildingequipmentspecificMROBOMs,lists(ortemplates)oftypicalwearablepartsarebuiltforeachequipment

class(ifcomponentfailureandcostanalysisdeterminessparepartsarerequired)presentattheplant.Inaddition,

amaintenancefactorisassignedtoeachequipmentclassthatranksthetendencyoftheparticularclassofequipmenttorequiremaintenance.

TheequipmentclassMROBOMtemplatesareusedasthe“standard”tobemodifiedasrequiredtofitindividual

equipmentrequirements.

AftertheindividualMROBOMsarecreated,formalanalysisisperformedtoassigninitialstockinglevelsbasedon:

Partcritical

Equipmentcriticality

Equipmentclassmaintenancefactor

Usageexposure(ThenumberoftimesthepartislistedonplantBOMs)

EachplanthasataminimumoneMROBOMchampion.Largerplantsmayhavespecialistsforsomeofthemaintenancecrafts.ForexampledifferentpeoplemayberesponsibleforoverseeingtheBOMsrequiredforrotatingequipmentandinstrumentation.TheMROBOMChampioncoordinatesallsparepartrequirementsandsparepartstockinglevels.ThepositionensuresthattheassignmentofexistingsparepartstoBOMsiscompleted.Inaddition,thepositionisresponsibleforprioritizingandguidingthemovementofallexistingequipmentthroughplantMROBOMmethodology.FinallythepositionisresponsibleforensuringthatMROBOMsfordeletedequipmentareremovedandthesparepartsareremovedfromstockortheirinventorylevelsareadjustedtofitnewservicerequirements.

TypicalBestPracticeMROBOMProcesses

Thefollowingtasks,listedchronologically,makeupthetypicalMROBOMprojectatapacesetterplant:

Equipmentpopulationisaccuratelycataloged&classed

Equipmentclassesidentified&assigned

Equipmentclassmaintenancefactorsassigned

Equipmentcriticalityassigned

BOMtemplatesdevelopedforappropriateequipmentclasses

BOMdevelopmentplaninplacebasedoncriticality&maintenancefactors

Newequipmentaddprocessinplace

TypicalBOMStructure

ThefollowinglistdepictsalloftheelementsthatcanbefoundinaMROBOM.Notallelementshavetobepresent,butlargeMROBOMsforcomplicatedequipmentwilltypicallyuseAssembliesandSub-AssembliestobreaktheBOMintomoremanageableviewswithagoalofreducingcrafttimelocatingtheneededparts.

Equipment

Assembly

Sub-Assembly

BOMRecordIdentifier

InventoryDescription

BOMDescription

InventoryOEMPartNumber

BOMItem,DrawingorReferenceNumber

OverhaulQuantity

TypicalBOMElementDefinitions

AssemblyorSub-Assembly:ActualsparepartordummyBOMrecordtowhichothersparepartsareattached.TypicallyusedtologicallybreakdownlargeBOMs

BOMRecordIdentifier:Theuniquerecordkeyconsistingoftheequipmentandinventoryrecordidentifiers

InventoryDescription:Thedescriptioncontainedinthesparepart’sinventoryrecord

BOMDescription;Alternateoradditionaldescriptiondescribingfunctionofsparepartontheequipment

InventoryOEMPartNumber:Originalequipmentmanufacturerpartnumber

BOMItemNumber:Item,referenceordrawingnumberrelatingthespareparttoitslocationontheOEMBOM

OverhaulQuantity:Numberoftimesthesparepartisusedintheequipmentorassembly

PotentialMROInventorySavings

Emersonhasfoundthatthesavingspotentialisbasedontheextenttowhichbestpracticesarefollowedintheseareas:

InventoryControl

BOMs

MaintenanceReliability

PM/PdM

RecurringProblemSolving

Emersonresearchonbestpracticesinindustryplants,includingpowergeneration,hasfurtherfoundthatthetypicalpossiblesavingsareintherangeof20%to50%.Again,thesavingspotentialdependsonthecurrentbestpracticesinplace.

DistributionofPotentialMROInventorySavings

Thesavingsdistributioncanbestbedescribedasacylinderdividedaccordingtothefollowingformula:

MaintenanceReliability(30%):ThefollowingassumptionswerederivedfromaNPRAstudyfortherefiningindustrybutare

applicabletoanyheavyindustry.

PM/PdM(15%):Savingsderivedovertimebyreducingequipmentfailureswhichinturnresultsinreducedpartusageandgraduallyallowlowersparepartstockinglevels.

RecurringProblemSolving(15%):Savingsderivedovertimebyrootcausefailureanalysisandtheimplementation

ofsolutionsdiscoveredasaresultofreliabilitycenteredmaintenance(RCM).Thesolutionsresultinreducedpartusageandgraduallyallowlowerstocklevels.

MROBOMs(30%):ThisassumptionwasmadefromEmersonresearch&assessmentresults.Beingthefocusofthereport,thissubjectisdiscussedingreaterdetailinthenextsection.

InventoryControl(40%):ThisassumptionisalsofromEmersonindustryresearch.Thisareaofsavingsresultsfromtheimplementationofbasicinventorymanagementmethodologies.Itincludesproceduressuchassecurity,cyclecounting,orderquantityandorderpointmodeling,accuratedescriptionsandtrackingkeyperformanceindicators.

PlantSavingsfromMROBOMs

Emersonhaspreviouslystatedthatamaximumsavingsequalto50%oftheMROinventoryvalueispossible.Theactualpotentialpercentageofsavingsisbasedonthecurrentstateoftheplant’sMROBOMprogram,thecurrentlevelofMROinventorymanagementandthesophisticationofthemaintenancereliabilityprogramattheplant.EmersonresearchindicatesthatMROBOMsareonaverage30%ofthetotalsavingsvalue.Thedirectinventorysavingscomefromeliminatingsparepartsnolongersupportingplantequipment,reductionofsparepartstockinglevelsbecausetotalpotentialneedforeachsparepartisnowknownandcanbemoreaccuratelyforecastandfromtheeliminationofduplicatesparepartsasaresultoftheMROBOMbuildingprocess.

Inaddition,MROBOMsresultinotherplantsavingsinareassuchasmaintenancelaborandthereductionofequipmentdowntime.Maintenancelaborsavingsofupto15%arepossible.Thesesavedhourscanbe“banked”inthePM/PdMprogram,whichwillresultinevengreatersavingsovertime.Thelaborsavingsarearesultofthedecreaseintimespentidentifyingandlocatingpartsneededforequipmentrepair.Emersonassessmentshavefoundthat10%to25%ofacraftsman’stimeisspentobtainingparts.BOMswilllargelyeliminatethiswasteandwillalsoallowforin-plantdeliveriesbythestoreroominlargeplantsbecausevisualidentificationofthesparepartbythecraftsmenisnolongerrequired.

Anotherareaofsavingsisfromequipmentdowntimeavoidance.Emersonhasbenchmarkedthissavingsat3.5%.Thissavingsisnormallycalculatedbasedonthevalueoflostproduction.However,sincethefocusofthisreportisonMROinventorysupplychainandnotmaintenancereliabilitythesavingspercentageandformulahasbeentiedtotheMROinventoryvalue.Thesavingscomefromthefactthatrequiredsparepartsarequicklylocatedthusreducingthemeantimetorepair.

Anotherareaofcostavoidanceresultsfrominstallingthecorrectsparepartandnotjustonethatfits.AccurateMROBOMsaddqualityassurancetothemaintenancerepairprocessbysignificantlyreducingthepossibilityofinstallingthewrongpartandpossiblycausingearlyandpotentiallycatastrophicfailureoftheequipment.Thisisextremelyimportantinhighlyregulatedindustriessuchasnuclearpowerandpharmaceuticals.

ThefollowingchartdepictsthesavingsavailablebyinstitutingavarietyofmaintenancebestpracticesincludingBOMs.

YourTotalPotentialBOMSavings

Toquantifythepotentialsavingsgainedbyhavinga“pacesetter”BOMprogram,EmersonhasdevelopedaMROInventorySavingsModelinanExcelspreadsheet.Thespreadsheetrequirestheinputofyourtotalplantmaintenancecosts,MROinventoryvalueandplantmaintenancelaborcostsintheBOMInputsheet.Inaddition,youwillbeaskedtobenchmarkthestatusofyourBOMprogramusingtheBOMSurveysheet.Usingthedatayouprovide,thespreadsheetwillcalculateanddisplaythetotalpotentialsavingspossibleintheCaseStudy$SavingsCalculations&Resultsworksheetportionofthemodel.Dataentryinstructionsareprovidedandexplanationsarecontainedinmanyofthesurveyquestioncellsofthespreadsheet.

Asampleofthecalculatorinputandoutputscreensaredisplayedintheappendixattachedtothisdocument.

InvestmentcosttogaintheMROBOMportionoftheMROInventorySavings

Toassistyouinestimatingtheinvestmentrequiredtoobtainthesavingspossiblefroma“pacesetter”MROBOMprogram,Emersonsuggeststhefollowingthumbrules,whichcanbeusedtocalculatetheman-hoursneedtobuildtheindividualMROBOMs:

Assume40%ofplantequipmentiscriticaltotheprocessandwillrequireBOMs

Assumeaverage2to4hoursperBOMdeveloped

AssumeonedevelopedBOMcanbecopiedto2to5piecesofequipment(dependentonplantequipmentcommonality)

Finally,assumethatwhilelaborsavingswillbeginimmediately,MROinventoryvaluesavingswilltaketwotofiveyearstoaccrue

oncetheMROBOMsareinplace.

AppendixA

BOMSavingsCalculatorSample

EmersonBOMSurveyInputScreenSample

ThesurveybelowreflectsthestateoftypicalBOMprogramsatplantsEmersonvisited:

InventorySavingsModel—BOMSurvey

Shadeindicatesinputpoint

MROInventoryImprovementAreas

Use"clearcontent"whenchanginganycheckboxselections

X

Area

Survey

SurveyCharacteristic

BOMs

WhichcharacteristicbestdescribesthecurrentstatusofyourBOMprogram?

AllsparepartsandappropriateconsumableshavebeenassignedtoallappicableBOMs

Checkonlyonebox.

AllsparepartsareassignedtoBOMbutmanytimesonlytotheequipmentBOMthepartwasoriginallyputinstockfor

Many,butnotall,sparepartsareassignedtoBOMs

AfewsparepartsareassignedtoBOMs

X

NoBOMs

BOMs

WhichcharacteristicbestdescribesyouruseofaspecialBOMdescription(overridingtheitemsinventory

description)fieldthatdescribestheuseofthepartinthespecificapplication?

AllapplicableBOMrecordsenhanced

Checkonlyonebox.

ManyBOMrecordsenhanced

AfewBOMrecordsenhanced

NoBOMrecordsenhanced

X

BOMs

WhichcharacteristicbestdescribesyouruseoftheBOMfield(orfields)thatcanbeusedtostorespecificdrawingnumbers,itemnumbers,orreferencenumbers

thatreflectapartsuseorlocationontheapplicableequipment'sexplodedpartsdrawingview?

AllapplicableBOMrecordsenhanced

Checkonlyonebox.

ManyBOMrecordsenhanced

AfewBOMrecordsenhanced

NoBOMrecordsenhanced

X

BOMs

Whichcharacteristicbestdescribesyourpopulationofthe"overhaulquantity"or"quantityofthepartused"fieldontheapplicationBOMrecords

AllapplicableBOMrecordsenhanced

Checkonlyonebox.

ManyBOMrecordsenhanced

AfewBOMrecordsenhanced

X

NoBOMrecordsenhanced

BOMs

WhichcharacteristicbestdescribesthestatusofyourprogramtoidentifyallyourOEMsubstitutesandassignthemtoBOMsinplaceoftheOEMpart?

AllappropriateOEMsubstitutesidentified

andassigned

Checkonlyonebox.

ManyappropriateOEMsubstitutes

identifiedandassigned

AfewappropriateOEMsubstitutes

identifiedandassigned

X

NoappropriateOEMsubstitutesidentified

andassigned

EmersonBOMSurveyResultsScreenSample

ThetablebelowreflectsthesurveyresultsoftypicalBOMprogramsatplantsEmersonhasvisited:

InventorySavingsModel—BOMSurveyResults

SurveyQuestions

MROInventorySavings

MaintenanceandStoreroomLabor

EquipmentDowntime

PossiblePoint

BOMProgramStatus

0

0

0

16.0

0

0

0

12.0

0

0

0

8.0

4

4

4

4.0

0

0

0

0.0

UseofspecialBOM

descriptionfield

0

0

2.0

0

0

1.0

0

0

0.5

0

0

0.0

Useofoptional

BOMfields

0

0

2.0

0

0

1.0

0

0

0.5

0

0

0.0

Useofoverhaul

quantityfield

0

0

2.0

0

0

1.0

0.5

0.5

0.5

0

0

0.0

UseofOEMsubstitute

0

6.0

0

4.0

2

2.0

0

0.0

TotalPointsfromSurvey

6

4.5

4.5

MaximumPossiblePoints

22

22

22

%ofMaximumPossiblePoints

27%

20%

20%

EmersonBOMSavingsCalculationsSample

Thetablebelowreflectsthesavingspotentialbasedonthemodelcalculations.NotethatthesavingspresentedbecauseofPM/PdM,RecurringProblemSolvingandInventoryControlSavingshavebeeninsertedasanexampletosupportthepresentedcasestudyandarenotactuallypartofthemodelcalculations.

InventorySavingsModel—$SavingsCalculationsfromBOMSurvey

CaseStudyInputs

CaseInputs

CaseAdjInputs

Shadeindicatesinputpoint

TotalAnnualMaintenance

$10,000,000

$10,000,000

TotalMRO$

$4,633,306

$4,633,306

TotalMaintenanceLabor$

$5,500,000

$5,500,000

BaseSavingsBenchmarks

MaintenanceReliability

BOMSavings

InventoryControlSavings

PM/PdM

RecurringProblemSol